Lubricating compositions and methods of lubricating



v Sept. 28, 1965 R. s. OWENS ETAL 3,208,940

LUBRICATING COMPOSITIONS AND METHODS OF LUBRICATING Filed March 19, 1962'lnvenfors Robert S, Owens,- Leon 5 5/. Pierre,

5y W and 7' heir Afforn e y- Preferably, R" does not exceed 30 carbon at"ms, although It will of course be longerchain radicals may be used.understood that mixtures of these olefins may be employed in thepractice of our invention. I The ester. component in thisparticular'class of lubri- -can ts,/which must be free of 'olefinicunsaturation, comprises a compound having the formula 1 (II) Q x z Z isa monovalent, linear, straight chain saturated aliphatic radicalselected from theclass consisting of linear alkyl and linear fluoroalkylradicals of from 11 to as' long as-4O carbon atoms or more, -X is adivalent radical se- O O I carbonyloxy (.O- (and the mirror-imagedJ-radical) sultoxy (S), and sulfonyl (-8-), X and Z together representthe monovalent group .XZ whicn encompasses the radicals OZ, SZ

whereZ is as previously defined. Qis a monovalent lower alkyl straightchain radical of from l'to 3 carbon In general, amounts of the olefin aslow as in the mixture give significant results. We have found that theolefin component advantageously is present in an amount equal to about595%, by weight, of the total Weight of the olefinand the othercomponent: represented by Formula II. Obviously, mixtures of the olefinsmay be used in combination with mixtures of the compounds represented byFormula II.

Because-of the ease of preparatiom'ready availability of raw materialsfor synthesis and their suitability and outstanding properties aslubricants and as additives to other well known lubricants, we prefer touse as the olefiniccomponent one which is a straight chain unsaturatedaliphatic hydrocarbon having olefinic unsaturation' example, mineraloils of lubricating viscosity, greases vmade from such lubricating oils,silicone lubricating oils,

atoms selectedfrom the class consisting of alkyl radicals andfiuoroalkyl radicals, e.g., methyl,- ethyl, propyl, fluoromethyl,difluoromethyl, trifluoromethyl, 1,2- difluoroethyl, perfluoropropyl,etc. v

' Included among the normal compounds (as contrasted to branched chaincompounds) represented'b'y Formula I are, for instance, decene l,dodecene-l,- tetradecene-l,

dodecene-Z, tetradecene-Z, pentadecen'e-l, hexadecene-l (cetene),octadecene-l', octadecene-2, 1-fiuor0tetradecene-l,1,2-difluorotetradecene-l, l-fiuorohexadecene-l, trifluorohexadecene-l,1,1,2,2 tetrafluorohexadecene-Z, etc., as well as mixtures of sucholefins.

Among the radicals which Z may be are, re".- example,

undecyl, dodecyl, tetradecyl, hexadecyl, 'pentadecyl, eicosyl, docosyl,tricosyl, triacontyl, tetracontyl, 1',1,l,2,2,- penctafiuorotetradecyl,tetrafluorododecyl hexafluorotetradecyl, etc.

Examples of compounds coming within the scope of. Formula II are, forinstance, methyl laurate, propyl laurate, methyl myristate, methylpalmitate, methylcarbonate, 'methyl tetradecyl sulfoxide, ethyl*hexadecyl sulfone, ethyl tetradecyl ether, ethyl eicosyl sulfide,methyl monofiuorononadecyl carbonate, fluoromethyl dodecyl ether, methyltetrafluorotricosyl sulfone, methyl hexafiuorotriacontyl sulfoxide,-propyl trifluoroundecyl ketone,

ethyl trifluorostearate, 2-fiuoroethyl octadecyl sulfide,l,2-difluoropropyl eicosyl ketone, fiuoroethyl tetrafiuorotricosylsulfone, methyl trifiuorotricosyl ether, etc- The proportions of the twoingredients can be varied widely and generally are. preferred in suchproportions that the combination of the'two imparts the desiredlubrieating characteristics and represents afiuid mixture which has asolidification temperature well below room tem perature, for example,below 15 0., thus makingthe lubricant useful over abroad spectrum oftemperatures.

.one' part to the other.

diester lubricating oils, polyester lubricating oils, silicate esterlubricating oils, etc. Aqueous emulsions of our lubricating composition,either alone or in combination, with other well known: cutting oils canbeused toadvantage in cutting and grinding applications. Our lubricantsare particularly useful in lubricating solid surfaces which moverelative to each other. where one of the surfaces is aluminum. When onesolid surface moves relative to another surface with a lubricant betweenthe two surfaces, there maybe a completefilm of lubricant separating thetwo surfaces or there may be varying degrees of contact between thesurfzicesJThe former condition exists under ideal hydrodynamiclubrication, while the latter condition is characteristic of boundarylubrication. Complete hydrodynamic lubrication may be obtained undercertain ideal conditions found in bearings but is influenced bysuchfactors as design of the two solid surfaces, load on the surfaces,and the relative speed of However, even under these conditions, boundarylubricatingproblems are encountered during stopping and starting,operations, and from a practica-lstandpoint, perfect hydrodynamiclubrication i is approached rather than attained. Therefore, the abilityof our lubricants to improve the boundary lubrication of solid surfacesmoving relative to each other where one of the surfaces is aluminum, isa feature which has been greatly desired in the past.

In addition to our lubricants improving the lubricating characteristicsof two solid surfaces where both surfaces are aluminum, it should alsobe understood thatou'r lubricants are also useful in those cases whereone of the surfaces is aluminum and the other surface is another solidmaterial, as, for instance, various metals, for example, iron,molybdenum, copper, tungsten, magnesium, zirconium,'chromium, nickel.etc., alloys of said metals, such as steels, brasses, the alloys ofmagnesium, cobalt, zirconium, beryllium, aluminum,.iron, zinc, etc. Inaddition, the other surface may be still other solid materials, forexample, wood, molded synthetic resins, laminates, etc., or specialcompounded compositions such as'porous metal, graphite, graphiteimpregnated metal, soft bearing alloy-s, e.g., babbitts, etc., or veryhard compositions, for example, metal carbides, nitrides, etc. Thelubrication of the above metals alone other than aluminum, by means ofour compositions is not precluded. Thus, the lubrication of surfaceswhere one of the surfaces is titanium, beryllium, tungsten, etc., usefulfor fabricating structural shapes is'included in the scope of theinvention.

Nominally, in the design of equipmeritiwhcre one solid surface movesrelative to another, both solid surfaces 'fide, tin sulfide, graphite,etc.,

be incorporated to produce a gel structure. Particularly are the samematerial if the wear is to be equal on both parts or one is made of amaterial softer than the other when the wear is to be essentially all onthe softer part.

' This is usually done when one part is easier to replace than the otheror the one part is being cut or shaped by the other.

the boundary lubricating properties of the latter. Generally, wehavefound that for a solid surface of aluminum where the other surfacemoving relative to the first is on of even small amounts, and, forexalso aluminum, the coefficient of friction is generally greatlyimproved where at least 50%, by weight, of the total lubricantconstitutes the mixture of the olefinic material and the compoundrepresented by Formula 11 above. On a weight basis we may use from l0 to90 parts of our lubricant mixture per 100 parts of the other usuallubricant. For the first time, this discovery permits the use of a widevariety of aluminum compositions in the fabrication of bearings and likesurfaces, since, as far" as we are aware, prior to our invention, no waywas satisfactorily known to preventgal-ling and seizing of bearings madeof aluminum. Although specific alloys of aluminum were made forbearings, the useof such compositlons required concessions to be made asto the bearmg clearances, life, etc., in order to provide adequateperformance.

Likewise, our lubricating compositions permit aluminum materials to beshaped, for example, by drawing, spinning, extrusion and the like,.witha very smooth finish. When our materials are used as the lubricantwithoutdilution, the aluminum composition can beformed with a smooth,mirror-like finish whichiisdifiicult to obtain by the use of previouslyknown lubricants. Typical examples of the various aluminum compositions(including aluminumfalloys) that can be lubricated by our lubricants arethose alkaline earth soaps of the fatty acids, but other soaps mayalsobe used, for example, zinc, tin, lead, copper, etc., soaps of the fattyacids. A particularly desirable grease composition may be made fromlithium stearate or lithium hydroxy stearate. These grease compositionsmay be made by any of the well known methods, for example, as disclosedin US. Patents 2,450,22l-Ashburn et al.;'2,450,- 222-Ashburn et al.; and2,260,625Kistler.

It will of course be apparent to those skilled in the art that inaddition, pour depressants, stabilizers, inhibitors, particularlyoxidation inhibitors, and the like, may be added to our lubricatingcompositions to impart to the latter the additional properties whichthese particular additives are designed for.

In order that those skilled in the art may better understand how thepresent invention may be practiced, the following examplesare given byway of illustration and not by way of limitation. In all of theexamples, the percentages are by weight.

The apparatus used to test our lubricants shown in the followingexamples under boundary lubricating conditions is described in theattached drawing, in figure shows partly in section the portion of astandard four-ball wear tester which has been modified to evaluatelubricating compositions using metals in various shapes other than theballs.

This .apparatus comprised a modified four-ball wear and their holderwith a cup and washer, as shown in the disclosed on pages 851-853 and865-958 of Metals Handbook,vol. l, Propetities and Selection of Metals,American Society for Metals, Novelty, Ohio, Eighth Edition (1961), forexample, the high purity aluminum alloys which are figure. Rider 1, madeof aluminum (or another metal), is cup-shaped and is rotated atpreselected speeds against stationary test washer 2 made also ofaluminum (or another metal) by means of a motor driven shaft 3 to whichrider 1 is attached by machine bolts 4 and 4'. Washer Z is rigidlyfastened'to the base 5 of chamber 6 by means of machine bolt 7 throughthe medium of a rubber member designed to insure proper alignmentbetween washer 2 greater than 99% aluminum, e.g., EC alloy, 1060 alloy,

1100 alloy, etc., alloys of aluminum with other metals, for example,copper, silicon, tin, zinc, etc., asare more fully described on pages955-958 of the above reference. Typical of the mineral, or hydrocarbonoils of lubricating viscosity are the hydrocarbon lubricants obtainedfrom petroleum. These products normally have viscosities in the range of25 to 10,000 Saybolt Universal Seconds (S.U.S.), and may be asingle-mixture of hydrocarbons. Typical of the-silicone lubricating oilsare those disclosed in, for example, US. Patents 2,4l0,346--Hyde;2,456,- 496- -Ford et al.; 2,469,888-Patnode; 2,469,-890-Patnode;2,970,162-Brown; etc.

Typical of the diester, polyester, and silicate ester lubricants arethose disclosed in US. Patents 2,450, 22 l--Ashburn et al.;2,450,222-Ashburn et al.; US. Patent 2,977,- 301-Bergen et al.; and onpages 16-24 of Technical Pub lication No. 77, published by AmericanSociety for Test ing Materials, Philadelphia, entitled, Symposium onSynthetic Lubricants. Other lubricating materials, as well as suitablemixtures of these lubricating materials, may

be used in the practice of our invention without departand rider 1. Areservoir of lubricant 8 under test is maintained around the testpieces. Chamber 6 rides on a series of ball bearings, one of which isshown as 9, which ride upon member 10, which forms the uppermost portionof plunger 11, which is connected to a hydraulic system (not shown) topermit. various loadings to be established between the two test samples1 and- 2. When rider 1 is rotated against test washer 2 by means ofclockwise rotation of shaft 3, chamber 6 will rotate upon member 10 Idue to the frictional force existing between members 1 and 2. The forcerequired to prevent such rotation is 0' measured by a strain gaugeattached to arm 12. This modification permits the coefiicient offriction to be calculated and examination of riders 1 and 2 permitsevaluation of the amount and type of wear produced.

Using this apparatus, the following measurements were made in thefollowing tests when the rider having a fiat annular surface area of0.393 square inch was rotated at 0.88 rpm. to give a surface speed of0.0461 inch per second against the test washer under of a load of 10 kg.These conditions represent operation in the boundary friction region andrepresent the most difiicult condition of bearing operation from alubricant standpoint. All percentages are by weight and the tests wererun at room temperature (about 22 C.) for one hour unless otherwisespecified. In some of the examples below the rider and washer were ofmaterials other than aluminum specifically stainless steel and titaniumin order to show the versatility of our lubricants.

EXAMPLE 1 In this example, a lubricant mixture consisting of cetene and30% methyl stearate was introduced in the above-described apparatus inwhich the rider and washer which the single 7 were both 403 stainlesssteel (115 43% chromium). The test for the ClllClUlltfy of the lubricantwas conducted for 1.5 hours at the end of which time it was found thatthe cocilicient offriction remained sleudy at around 0.16. Examinationof the wearsurl'acc of the washer showed ic-discernible wear with theexception thatitwas highly polished. For comparison, when cetene alonewas tested under the same conditions using the same stainless steelwasher and rider the coefficient of friction was quite erratic andshowed a wide scatter between 0.27 and 0.4.- In addition, the surface ofthe washer showed dcepgroov -ing indicating excessive wear.

EXAMPLE 2 the lubricant mixture in the above-identified apparatus inwhich the rider and washer were both alumihum.- Additionally, cetenealone (methyl stearate a sol-{d at room.

temperature) and cetane alone, were also-tested for comparison purposesto show the unexpected advantages of tions as lubricants in the abovedescribed test apparatus,

mixtures of 'cetene with either n-butyl stearate or isopropyl stearate,were also evaluated. Finally, a vegetable oil (corn oil) was tested toshow the effect of having poly-. unsaturation in one ester molecule.This vegetable oil consisted essentially of glycerides of fatty acidscontaining, on a weight basis, acid residues of the following acids; 34'to 62% linoleic acid, 19 to 49% oleic acid, 0.2 to 1.6% hexadecenoicacid, 8 to 12% palmitic acid, and less than 5% of small amounts ofmyristic and stearic acids. The 150 SUS hydrocarbon-oil was a minerallubricating oil of 150 Saybolt units viscosity widely employed as alubricant for bearing surfaces. Table l shows the compositions of thetest lubricants, the proportions of the lubricants and remarks as to thetype of wear encountered in each instance.

Table 1 Average Y r Lubricant Coetficient Remarks as to Wear of FrictionSurface 100% cetene 0.11 Very high wear as though the surface weremachined; Vegetable Oil 0. 27-0 38 Galled badly. 20% methyl stearate,80% cetene; 0 1 Veryl little wear after 1 our. 30% methyl stcaratc, 70%cctcne 0 1 Polished surface; No

visiblewear. 40% methyl stearate, 60% cetene 0. 1 Do. 50% methylstearate, 50% cetene- 0. 09 Do. 30% methyl stearate, 70% n- -decene-1 0.11 D0. 30%isopropylstearate, 70% eetenes 0 l-O. 24 Grooved and gelled in40 minutes. 20% n-butyl stearate, 80% eetene 0. 14-0 4 Ggoeleed andgalled a y. 50% n-butyl stearate, 50% cctcne 0 l2-0. 34 Badly gelled.100% 150 SUS hydrocarbon oil 0. 2-0 7 Galled. 20% methyl stearate, 80%150 S US oil 0. 20. Do. 100% eetane l v 0. 4- 0. 68 Galled badly,seized. methyl stem-ate, 70% cetan 0. l4 Galled,

I At all times during the test, the coellieient. of friction was erraticand varied within the limits set forth.

EXAMPLE 3 In this example employing the lubricating test equipmentdescribed above in which both the rider and the washer were made oftitanium, a mixture of 70% cetene and 30% methyl stearate wereintroduced as the lubricant mixture in the apparatus. For comparison andas a control a hydrocarbon oil specifically SAE-lO spindle oil was usedas a lubricant under the same conditions. After conducting the weartest, it was found that the average coeiiicicnt of friction using thespindle oil was quite crratic and ranged from about 0.56-0.68; the testdisc or washer was badly gallcd and caused grooving during the l-hourrun. In contrast to this employing the mixture of cetene and methylstcarate, the average coefiicie'nt of friction was of the 'order ofabout 0.5-0.6 and the washer showed only a very slight wear track.

EXAMPLE 4 When a mixture of 50% tetradecene-Z is mixed with 30% ethyltetradccyl ether and this mixture isemployed as alubricant between twosurfaces of aluminum that is both the rider and washer were aluminum inthe above test equipment, the coefficient of friction is much lower by amagnitude in kind and the wear is materially reduced than when eitherthe aforesaid ether or tetradecene is used separately as the lubricant.The wear is also much less than when a hydrocarbon oil is employed asthe lubricant: g

Itwill bev clearly apparent that our compositions can be used not onlyin bearing applications where a shaft, for instance, is revolving inintimate contact with a stationary member, but they can also be employedin other applications as, for instance, in the cutting of aluminum,

. the extrusion, drawing and stamping of aluminum mem- .in thelubricating art, particularly underfboundary lubricating conditions.

bers, etc. Aluminum cans can be readily drawn to be used for capacitor"casings. Furthermore, billets of aluminum can be passed through dies andthe diameter of the billets greatly reduced in size to give aluminumwire which has a shiny appearance and, because of the smooth surfaces ofthe aluminum, 'reflects the advantageous lubricating characteristics ofour lubricating compositions. This ability to impartsmooth shinysurfaces recommends these compositions as polishing materialsfor soleplates of sadirons. Fractional horsepower motors( such asthose describedin our copending application Serial No.'1 01,917,

filed April 10, 1961,'and in the continuation-impart filed concurrentlyherewith based on that application, which by reference are made part ofthe disclosures of the instant application), using aluminum shafts andbearings can be advantageously lubricatedlwith our lubricatingcompositionseither alone or dissolved to the desired concentrationin ahydrocarbon lubricating oil.

It will also-be apparent to, those skilled in the art that, instead ofthe particular olefins and the methyl 'stearate used in the foregoingtests, other-olefins and compounds conforming to Formula I andFormula IImay be used without departing fromv thescope of the invention. Theproportions of ingredients can of course be varied widely,

and it will also be obvious that other lubricating compositions, manyexamples of which have been given above, can be combined with ourmixture of ingredients comprising the olefinic compound and thecompounds of Formula II to give compositions of matter having utilityWhat we claim asnew and desire to secure by Letters Patent of the UnitedStates is:

1.;A composition of matter comprising on a weight basis (a) from 5 to ofan'olefin having the formula 9 alkyl and linear fluoroalkyl radicalshaving from 8 to 30 carbon atoms, X is a divalent radical selected fromthe group consisting of -S- and Z is a monovalentlinear straight-chainsaturated aliphatic radical selected from the group consisting of linear,alkyl radicals having from 11 to 40 carbon atoms and linear fluoroalkylradicals having from 11 to 40 carbon atoms, and Q is a lower,straight-chain alkyl radical of from 1 to 3 carbon atoms.

2. A lubricating composition of matter comprising by weight, from 5 to95% methyl stearate and from 95 to 5% cetene.

3L A lubricating composition of matter comprising, by..

silicone, diester, hydrocarbon, polyester, and silicate esterlubricating fluids, and (2) from '10 to 90 parts-of amixture'of-ingredients comprising on a weight basis (a) from 5 to 95% ofan olefin havingthe formula and (b) from 95 to 5% of a compound havingthe formula whereR is a monovalent radical selected from the classconsisting of hydrogen andfluorine, R is a monovalent radical selectedfrom the class consisting of hydrogen fluorine, methyl,monofluoromethyl, difluoromethyl, and trifluoromethyl, R" is amonovalent linear straight-chain alkyl radical selected from the classconsisting of linear alkyl and linear fluoroalkyl radicals having'from 8to 30 carbon atoms, X is a divalent radical selected from thegroupconsisting of --O-, -S-

and

and Z is'a monovalent linear straight-chain saturated aliphatic radicalselected from the group consisting of linear alkyl radicals having from11 to 40 carbon atoms and lin-- ear fluoroalkyl radicals having from 11to 40 carbon atoms, and Q is a lower, straight-chain alkyl radical offrom 1 to 3 carbon atomsl 1 g 6. A lubricating composition comprising amixture of ingredients containing, on a weight basis (1) 100 parts of alubricating fluid selected from the class consisting of silicone,diester, hydrocarbon, polyester, and silicate ester lubricating fluids,and (2) from to 90-parts of a mixture of ingredients comprising on aweight basis (a) from 5 to 95% methyl stearate, and (b) from 95 to 5%cetene.

7. The method of lubricating two solid surfaces between which there isrelative motion, at least one of said surfaces being a metal, whichcomprises maintaining between the two surfaces a composition of mattercomprising on a weight basis (a) from 5 to 95% of an olefin having theformula and (b) from 95 to 5% of a compound having the formulatrifluoromethyl, R" is a monovalent linear, straight-chain alkyl radicalselected from the class consisting of 'linear alkyl and linearfluoroalkyl radicals having from 8 to carbon atoms,.){ is a divalent.radical selected from the group consisting of 0,

' and Z is a monovalent linear straight-chain saturated aliphaticradical selected from the group consisting of linear alkyl radicalshaving from ll to 40 carbon atoms and linear fluoroalkyl radicals havingfrom 11 to 40 carbon atoms, and Q is a lower,- straight-chain alkylradical of from 1 to 3-carbon atoms, and thereafter effecting motionbetween the two solid surfaces with the mixture of ingredientsthereb'etween.

8. The method of lubricating two solid surfaces between which there isrelative motion, at least one of said surfaces being a metal selectedfrom the class consisting of aluminum and alloys of aluminum, whichcomprises main ing between the two surfaces a mixture of ingredientscomprising on a weight basis (a) 1510 methyl stearate and (b) from 95 to5% cetene, and thereafter effecting motion between the two solidsurfaces with the mixture of ingredients therebetween.

'9. .The method of lubricating two solid surfaces between which there isrelative motion, at least one of said surfaces being a metal selectedfrom the class consisting of aluminum and alloys of aluminum, whichcomprises maintaining between the two surfaces a mixture of ingredientscomprising on a weight basis (a) 5 to 95% methyl stearate and (b) from95 to 5% decene-l, and

thereafter effecting motion between the two solid surfaces with themixture of ingredients therebetween.

10. The-method of lubricating two solid surfaces between which there isrelative motion, at least one of said surfaces being aluminum, whichcomprises maintaining between the two surfaces a mixture of ingredientscomprising on a weight basis (a) 5 to 95% ethyl tetradecyl ether and (b)from 95 to 5% tetradecene-2, and thereafter effecting motion between thetwo surfaces with the with the mixture of ingredients therebetween.

11. The process for shaping a metal composition which comprisesmaintaining a film of lubricant between the metal composition and ashaping member, said lubricant comprising on a weight basis (a) from 5to 95% of an and '(b) from 9 5 to 5% of a compound having the formulaconsisting of hydrogen and fluorine, R is a monovalent olefin having theformula where R is a monovalent radical selected from the class radicalselected from the class consisting of hydrogen fluorine, methyl,monofluoromethyl, difluoromethyl, and

trifluoromethyl, R" is a monovalent linear, straight-chain alkyl radicalselected from the class consisting of linear 11 v a I '12 alkyl andlinear fiuoroalkyl radicals having from 8 to 30 12. The process as inclaim 11 in which the metal comcarbon atoms, X is a divalent radicalselected from the position undergoing shaping is an aluminum compositiongroup consisting of -O, S, selected from the class consisting ofaluminum and alloys 0 0 0 v 0 0 of aluminum of which 50%, by weight, isaluminum, ll I5 0 o l] g m g 5 and the lubricant is a mixturecomprising, by weight, from 5 to 95% cetene andfrom 95 to 5%methyl-stearate.

and Z is a monoyal'ent-linear straight-chain saturated ali- ReferencesCited by the Examiner phatic radical selected from the group consistingof linear UNITED STATES PATENTS alkyl radicals having from 11 to 40carbon atoms and 10 2 210140 8/40 colbcth, linear fluoroalkyl radicalshaving from 11 to 40 carbon 1 2257'969 10/41 Loam 'g 'f"'i 2 atoms, andQ is a lower, straight-chain alkyl radical of 25o0165 v 3/50 Doheny ctfrom 1 to 3 carbon atoms, and thereafter subjecting the 11/53 Kipp 252*XR metal composition to sufiicient force to create relative. motionbetween said metal compositionand said shaping 15 1/56 wankat 252 Xmember and to cause displacement of a portion of said DANIEL primaryExamine, metal-composition with respect to the remainder thereof.

1. A COMPOSITION OF MATTER COMPRISING ON A WEIGHT BASIS (A) FROM 5 TO95% OF AN OLEFIN HAVING THE FORMULA